Time. Actions. That's what trust is about. His words are meaningless now. Only time and actions can replace all the quacking.
And I do like the sponsor idea, but then again...its you forcing him. He is a grown up, he should figure this out himself. He shouldn't need to ask you these questions - he can google 'how to earn back a womans trust' and find lots of information at his fingertips.
It's a manipulation - because if you give him a set of tasks and he does them - he's got you cornered. If you kindly and gently put the responsibility ball back in his court, he is left to either pick it up and move forward, or not.
and here's the kicker with time - you may have a different window then he does. I've been coming to that realization...I am on a different life path here and it may be that in the end, timing never does work out for us. But that's ok. Then it wasn't meant to be anyway, ya know?! Trust your intuition on this one. Only you know what works for you.